Conventionally, stockings and socks (hosiery) are knitted in the order of a leg portion, a heel portion, an instep portion, and a toe portion. The heel portion and the toe portion are knitted by increasing and decreasing stitches along a gore line. The heel portion and the toe portion of hosiery are knitted by a picker device that has an up-picker and a down-picker. Conventionally, the leg portion and the instep portion are knitted by continuously rotating a knitting cylinder of the knitting machine. On the other hand, when the heel portion and the toe portion are knitted, the knitting cylinder is switched to oscillation or alternate forward and backward rotation. When the heel portion or the toe portion is knitted, the number of stitches is gradually decreased and then increased. When the stitches are decreased, a butt of a knitting needle is raised by an up-picker and the knitting needle is moved to a non-knitting level over a center cam. On the other hand, when the stitches are increased, a knitting needle in the non-knitting level is lowered to a knitting level by a down-picker. Whenever the knitting cylinder of the knitting machine is oscillated or rotates forward and backward, the up-picker and the down-picker are abutted by butts of knitting needles at their forward ends, thereby raising and lowering the respective knitting needles. Conventionally, a pair of up-pickers are provided. These up-pickers are referred to as a left-side up-picker and a right-side up-picker. These up-pickers are connected by a connecting member so that they move in liaison in vertically different directions. A plate-shaped picker cam is used to raise the up-picker while holding a needle butt. Likewise, for the down-picker, another picker cam is used. This picker device is disclosed in Japanese Patent Laid-Open Publication No. 31-8933.
In the above described device, when the frequency of the oscillating motion of the knitting cylinder becomes high as the speed of the knitting machine is increased, there occurs wear of the connecting plate connecting the left-side up-picker and right-side up-picker and the connecting pins therebetween. Thus, the knitting operation becomes unstable and thereby the knitting machine malfunctions with resultant lack in reliability. In addition, since the construction of the picker device is complicated, the assembling, adjustment, maintenance and inspection become troublesome.
In the preceding paragraph, problems involved in the conventional up-picker and down-picker were described with respect to the ordinary plain knitting and tuck knitting.
On the other hand, when a variety of patterns are knitted, one to four yarn feeders for knitting motif patterns may be provided along with one or two ground yarn feeders for knitting jacquard patterns. When four pattern yarn feeders are provided, a motif pattern with four colors can be knitted.
For example, in the case of knitting a jacquard pattern wherein the width of the pattern is narrow, no problem will occur even if the width of a knitting needle group in a knitting course is narrower than the width of the front end of the down-picker. On the other hand, if the width of the knitting needle group in the knitting course (that is the width of a region lacking the knitting needles in a non-knitting course) is greater than the width of the front end of the down-picker, the front edge of the down-picker is raised, in the knitting needle lacking region, from a low non-operative position to a high position immediately below a leveling cam. Thus, knitting needles that should not participate in the pattern knitting come in contact with the front end of the down-picker. Consequently, the knitting needles are lowered from the non-knitting level to the knitting level, thereby disordering the jacquard pattern of the instep portion and making it impossible to knit the heel portion.
Objects of the present invention are to solve the above described problems. A main object of the present invention is to provide a picker device of hosiery knitting machine that can prevent wear of a connecting portion of an up-picker and a down-picker and that can be relatively simply constructed.
Another object of the present invention is to provide a picker device of hosiery knitting machine that can correctly knit a jacquard pattern without defect of a heel portion even if the width of a knitting needle lacking region in a non-knitting course is greater than the width of the front end of a down-picker.